Method for the continuous production of aqueous dialkali salt solutions of aromatic dihydroxy compounds

Abstract

In a process for continuously producing solutions of dialkali or dialkaline earth metal salts of aromatic dihydroxy compounds, the aromatic dihydroxy compound is sprayed in the form of a melt onto a turbulent liquid film of a solution of an alkali or alkaline earth metal hydroxide. The alkali or alkaline metal hydroxide is preferably solved in water.

What we claim is: 
     
       1. A process for continuously producing solutions of dialkali or dialkaline earth metal salts of aromatic dihydroxy compounds, wherein an aromatic dihydroxy compound is sprayed in the form of a melt onto a turbulent liquid film containing the alkali or alkaline earth metal hydroxide in aqueous solution. 
     
     
       2. A process as claimed in claim 1, wherein the solution of an alkali or an alkaline earth metal hydroxide is an aqueous solution. 
     
     
       3. A process as claimed in claim 1, wherein the liquid film is produced in a reactor by tangentially introducing a stream of the solution of the alkali or alkaline earth metal hydroxide and the molten dihydroxy compound is sprayed through nozzle. 
     
     
       4. A process as claimed in claim 1, wherein the dihydroxy compound is bisphenol A, 1,1-bis-(4-hydroxy-phenyl)-cyclohexane, tetramethyl bisphenol A, tetrachloro bisphenol A or tetrabromo bisphenol A and the solution of an alkali or an alkaline earth metal hydroxide is an aqueous solution of sodium hydroxide. 
     
     
       5. An apparatus for carrying out the process claimed in any preceding claim comprising at least two insertion tubes connected to a ring pipe, leading into a reactor through inlets and forming an angle of less than 45° with the wall of the reactor. 
     
     
       6. A process as claimed in claim 1, wherein said production is performed in a cylindrical reactor by introducing and contacting the aromatic dihydroxy compound and the metal hydroxide in an upper portion of the reactor for reaction thereof to form said solution of dialkali metal salt, said solution of dialkali metal salt is withdrawn from a bottom portion of the reactor, the turbulent liquid film is produced in said upper portion of the ractor by tangentially introducing a solution of the metal hydroxide into the upper portion of the reactor, and tangentially introducing a portion of the withdrawn solution of dialkali metal salt into the upper portion of the reactor, the amount of solution of dialkali metal salt so tangentially introduced being 0.5 to 20 times the amount of solution of the metal hydroxide so tangentially introduced. 
     
     
       7. A process as claimed in claim 6, wherein the solution of dialkali metal salt is cooled in the reactor. 
     
     
       8. A process as claimed in claim 6, wherein the average residence time of the solution of the dialkali metal salt in the reactor is between 0.5 and 20 minutes. 
     
     
       9. A process as claimed in claim 1, wherein the aromatic dihydroxy compound is dihydroxy diarylalkane. 
     
     
       10. A process as claimed in claim 1, wherein the aromatic dihydroxy compound is at least one of 4,4'-dihydroxy-2,2-diphenylpropane; 4,4'-dihydroxy-1,1-diphenylcyclohexane; 4,4'-dihydroxy-3,3',5,5'-tetramethyl-2,2-diphenylpropane; 4,4'-dihydroxy-3,3',5,5'-tetrachloro-2,2-diphenylpropane; 4,4'-dihydroxy-3,3',5,5'-tetrabromo-2,2-diphenylpropane. 
     
     
       11. A process as claimed in claim 9, wherein the metal salts are soluble in water. 
     
     
       12. A process as claimed in claim 1, wherein the average residence time is about 0.5 to 20 minutes.